$ D = \left[\begin{array}{rr}9 & 4 \\ 1 & 7\end{array}\right]$ What is $ D^{T}$ ?
Solution: To find the transpose, swap the rows and columns. $ D^{T}$ = $\left[\begin{array}{rr}9 & 1 \\ 4 & 7\end{array}\right]$